Amplifier Trouble

I have a Kenwood KAC728S amp.  I have installed this amp in a couple of different cars I have had in the past.  I tried installing it today however everytime I put juice to it I am blowing both of the 20 amp fuses installed in the amp (I also have a 40amp inline fuse that hasn't blown yet).  I am using a new wire kit that I bought yesterday, 8ga power and ground.  I have it grounded to the body.  I am fairly confident the power wire that I installed today is not shorting on the body anywhere, although I have not scowered over every sq millimeter of it to be 100% positive.  The amp is several years old, so my question is, could I have a bad amp?  or am I missing something somewhere else?  Is there a test that I can run with a volt/ohm meter to confirm that I have a bad amp?

Thanks in advance!

Thanks for the quick reply.  I didn't think to check without the speakers or RCA cables.  I put in two new fuses and removed both the speaker cables and the patch cables and blew both the fuses again.   I am not a pro with an ohm meter so let me explain the process I used to check the ground to make sure I am telling you an accurate reading.  I used the 200 scale on my ohm meter and put the red lead to a bolt on my body and put the black lead to the 8ga ground cable that I was using to ground my amp and I am seeing a reading of 0.3 ohms.  So after reading the post on grounding that's probably okay, right?

Thanks again.